In recent years, the intramedullary nail has gradually gained importance and is becoming a standard method of internal fixation. Since the development of this method by Kuntscher, the intramedullary nail has broadened its range of indications (e.g. locking nail, Gamma nail, reconstruction nail).
The basic concept behind nailing has remained the same, namely the introduction of a tube or full cylinder into the medullary cavity of a tubular bone. Initially, nailing was used for the femur, but now, its application has been extended to include all large tubular bones. Until now, the cross-sections of intramedullary nails have remained more or less the same. Even the cloverleaf cross-section developed by Kuntscher some 50 years ago is still being used today, even though it has been proven that this shape brings no special advantages. Additionally, changing the cross-section from the circular or almost circular cross-section was never considered necessary before, since the medullary cavity of the various tubular bones was usually opened using a rotating or circular cutting device.
Today, more attention is being paid to the rate of fracture healing, and it is believed that healing occurs faster if less damage is done to the bone during placement of an implant in the body. By choosing an appropriate cross-sectional shape for an intramedullary nail which corresponds to the anatomy of the medullary canal, it is possible to eliminate unnecessary removal of bone and tissue from the medullary canal, thus promoting healing by minimizing damage to the medullary canal and its vascularization.
The choice of nail cross-section is particularly relevant for the humerus bone, in which the medullary canal is not round along its entire length but is in fact flat and thin in the distal part. For this bone, a nail with the typical circular or almost circular cross-section would not be appropriate. A nail with a flattened cross-section would be more suited for the distal humerus.